The semiconductor integrated circuit (IC) industry has experienced rapid growth. As the semiconductor industry continues on its path to improve its productivity and profitability, technological advances in semiconductor materials and IC designs have produced smaller and more complex circuits. These advanced materials and designs have been realized as the processing or manufacturing-related technologies and have also advanced. In the course of semiconductor evolution, functional density (defined as the number of interconnected devices per unit of area) has increased as the feature size has decreased. A scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. One of the developments is the replacement or supplementation of a conventional planar metal-oxide-semiconductor field-effect transistor by a vertical field-effect transistor. However, existing vertical field-effect transistors have not been satisfactory in all aspects, and similar developments of tools and methods for improving the performance of the semiconductor device are needed.